"[Del Toro and I] both walked away from Hellboy 2 agreeing that there would never be another one," he told IGN.

"But, with the passage of time, it became clear to me that he really always designed it as a trilogy. [Guillermo] has a very well-articulated idea of what the resolve would look like and it's amazingly theatrical and is epic in scope and would make for amazing cinema, with or without the first two movies.

"I said [to Guillermo], 'You owe it to the world to finish this trilogy' - I've been giving him Jewish guilt."

Hellboy creator Mike Mignola has repeatedly expressed doubt about a third movie based on his comic.